Steering system

ABSTRACT

There is disclosed a mechanism for stationarily supporting an operation panel mounted on a steeering wheel of a movable body. This mechanism includes two external gears between which said steering wheel is interposed, and two satellite gears resiliently urged toward the external gears. One of the external gears is stationary and the other has an operation panel secured thereto. Two satellite gears are rotated in the same direction and as a result, the operation panel is rotated in the opposite direction to that of the steering wheel and keeps substantially stationary. Further, there is disclosed a signal transmitting system for a radiotelephone in the movable body. A microphone is provided on the operation panel and a speaker unit is located at any position in the movable body. A duplex signal transmitting path having a howling control function is provided between the microphone and the speaker unit.

DESCRIPTION

1. Technical Field

The present invention relates to a steering system, in particular amechanism for mounting an operation panel of a radiotelephone on the topsurface of the rotating shaft of a steering wheel with which a movablebody such as automobile or the like is equipped, said radiotelephoneincluding push buttons and adapted to be installed in the movable body,and a system for transmitting signals between the operation panel andthe base unit of the radiotelephone.

2. Background Art

In a movable body such as an automobile or the like, the steering wheelis located nearest the driver and accessible to his hands. In order toimprove the handling by the driver of the operation panel including keyswitches for control and instruction of various units installed in theautomobile, it is desirable to mount the operation panel on the topsurface of the rotating shaft of the steering wheel.

Further, in the case of the movable body such as automobile or the likewhere a radiotelephone is installed, there is no way other than tolocate the base unit of the radiotelephone at the position far away fromthe speaker including the driver. Consequently, in order to prevent thesurrounding noise from being transmitted through the telephone, amouthpiece section such as a microphone or the like is designed to beseparatable from the base unit of the radiotelephone while both areconnected with each other through a cord so that the mouthpiece sectioncan be accessed by the speaker when he wishes to speak through theradiotelephone. However, while the driver is speaking through such atype of radiotelephone, he needs to keep holding the microphone or thelike with at least one of his hands. As a result, he often drives a cardangerously with only one hand. It is preferable to enable the driver tospeak safely while driving because he has many chances to speak throughthe radiotelephone installed in the automobile or the like.

In order to resolve the above-mentioned problem, Japanese Patent PublicDisclosure No. 59-32542 discloses a technology. According to thedisclosure, a steering apparatus of an automobile is equipped with aradiotelephone, an operation panel of which is mounted on the topsurface of the rotating shaft of a steering wheel. The operation panelincludes operation keys such as number keys and control keys of theradiotelephone, and a microphone. Such a radiotelephone that has theoperation panel mounted on the top surface of the steering wheel needsan additional mechanism for enabling the operation panel to keepsubstantially stationary without rotating together with the steeringwheel.

In the disclosure, there is shown a mechanism for stationarilysupporting the operation panel, said mechanism comprising a firstexternal gear fixed on a column cover positioned under the spoke of thesteering wheel, the steering shaft of which passes through the firstexternal gear and is freely rotatable therein, a second external gearrotatably supported on the upper end of the steering shaft which extendsover the spoke of the steering wheel, an operation panel fixed on theupper surface of said second external gear, a rotating shaft verticallypassing through the spoke integrally formed with the steering shaft,said rotating shaft being rotatable in the spoke, and satellite gearssecured to the upper and lower ends of said rotating shaft and adaptedto engage said first and second external gears. This mechanism allowsthe operation panel to rotate in the opposite direction to that in whichthe steering wheel is rotated and by the same rotational angle as thatthereof. Consequently, the operation panel can remain substantiallystationary even when the steering wheel is rotated.

The stationary supporting mechanism is so designed that the rotatingshaft of the two satellite gears which is adapted to engage the firstand second external gears passes through the spoke and is freelyrotatable therein. Because of this arrangement, in order to alwaysensure suitable engagement between the two external gears and thesatellite gears, it is necessary to precisely position the through holefor the rotating shaft, resulting in the requirement of high precisionin design. Additionally, in assembling the arrangement, a bearing isfitted into the through hole, the rotating shaft is inserted into thebearing, and at the same time, the satellite gears secured to theopposite ends of the rotating shaft are brought into engagement with thetwo external gears. Therefore, this has a low operational efficiency.Besides, the satellite gears cannot follow the external gears when theexternal gears move eccentrically. As a result, the second external gearmoves at a different speed from the spoke, leading to failure to keepthe operation panel stationary.

In the system wherein a microphone is provided on the operation panel,the microphone is remote from the driver's mouth compared with the casewhere he speaks through the transmitter of a handset, and thereforetogether with his voice noise is likely to enter the microphone.

In order to resolve this problem, the system according to theabove-mentioned disclosure includes a pair of microphones positioned ata predetermined distance from each other on the operation panel anddirected at the driver's mouth, the output terminals of the microphonesbeing respectively connected with different input terminals of adifferential amplifier. According to this system, the differentialamplifier amplifies the difference between the audio signal entering oneof the microphones and the audio signal entering the other, resulting inan offsetting of same-phase noise which has laterally entered themicrophone, greatly amplifying only the signal representing the driver'svoice.

This system enables noise to be reduced to some degree. However, thesystem can not control the occurance of howling wherein the sound comingout of the speaker unit enters the microphone which in turn amplifiesthe audio signal, and then the amplified signal again comes out of thespeaker and returns to the microphone, a cycle which is repeated,resulting in gradualy increasing sound from the speaker unit.

DISCLOSURE OF INVENTION

The first features of the present invention are directed to animprovement of the operation panel wherein the rotating shaft of thesatellite gears is designed to be resiliently urged toward the externalgears instead of passing through the spoke. In a preferable example, aresilient member such as leaf spring or coil spring is used forresiliently urging the rotating shaft of the satellite gears toward theexternal gears and is connected at its one end with the spoke or therotating shaft either directly or through another member.

The system according to the present invention is so arranged that thesatellite gears are resiliently urged toward the external gears and,therefore, the system enables the satellite gears to always follow thepossible eccentric movement of the external gears. Accordingly, it isnot necessary according to the present invention to take intoconsideration the position of the through hole for the satellite gearaxis, unlike the prior art, and freedom of design is greatly improved.The present invention has advantages in work efficiency because inassembling the system, it is merely necessary to previously couple thesatellite gear shaft with the resilient member and later mount them onthe spoke.

The second feature of the present invention is directed at a howlingcontrol system. According to the present invention, between themicrophone and the base unit of the radiotelephone is provided a signaltransmitting path including a light transmitting path where a phaselocked loop (PLL), an automatic gain control (AGC), and a level balancerare connected with each other in series. After the level balancer hasbeen once regulated and set at a certain howling level, the AGCautomatically controls the gain of the output of the PLL within therange of the set howling level in response to the surrounding noise,resulting in change of the sound level. According to the presentinvention, a plane wave speaker unit is used to facilitate the howlingcontrol by the phase control.

The present invention, in comparison with the conventional signaltransmitting system using only frequency modulation, enables howlingcontrol to be effected by using phase modulation. Consequently, thepresent invention provides a solution for the problem in the prior artwherein it is difficult to perform duplex signal transmission due to theoccurrence of howling.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic perspective view showing one embodiment of themechanism according to the present invention for stationarily supportingthe operation panel on the steering wheel;

FIG. 2 is a schematic plan view of the mechanism as shown in FIG. 1;

FIG. 3 is a schematic plan view showing another embodiment of themechanism according to the present invention for stationarily supportingthe operation panel;

FIG. 4 is a schematic plan view showing yet another embodiment of themechanism according to the present invention for stationarily supportingthe operation panel;

FIG. 5 is a plan view of the operation panel;

FIG. 6 is a block diagram showing the signal transmitting system betweenthe operation panel and the base unit of the radiotelephone; and

FIG. 7 is a perspective view showing the steering wheel, the driver'sseat and the other neighboring instruments of the automobile which isequipped with the operation panel stationarily supporting mechanism andthe signal transmitting system according to the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

FIGS. 1 to 4 show the embodiments demonstrating the first feature of thepresent invention.

Referring to FIG. 1, a first external gear 1 is fixed to a column cover2 which is secured to the frame of the automobile. A steering shaft 3passes through the center of the column cover 2 and extends upwardlythrough the first external gear 1. The steering shaft 3 is arranged sothat it can freely rotate in the first external gear 1. The steeringshaft 3 further extends upwardly through the spoke 4 of the steeringwheel 80 (see FIG. 7). A second external gear 5 is rotatably mounted onthe portion of the steering shaft 3 over the spoke 4. The spoke 4 issecured to the steering shaft 3 so that the former can be integrallyrotated with the latter. A rotating shaft 6 extends parallel to thesteering shaft 3. Satellite gears 7 and 8 are secured to the oppositeends of the rotating shaft 6 and adapted to engage the first and secondexternal gears respectively.

In the embodiment as shown in FIGS. 1 and 2, a leaf spring 9 is used asthe resilient means which urges the rotating shaft 6 toward the steeringshaft 3 so that the two external gears 1 and 5 are kept in engagementwith the two satellite gears 7 and 8 at all times. One end of the leafspring 9 is secured to the spoke 4, while a bearing 6a for the rotatingshaft 6 is provided at the other end of the spring leaf 9. The resilientforce of the leaf spring 9 is not so high as to prevent the secondexternal gear 5 from rotating but is enough to make the satellite gearsfollow the external gears.

In the embodiment as shown in FIG. 3, a rod 10 and a coil spring 11 areused as the resilient means which urges the rotating shaft 6 of thesatellite gears 7 and 8 toward the steering shaft 3. One end of the rod10 is pivotably mounted to the spoke 4, while a bearing 6b for therotating shaft 6 is provided at the other end of the rod 10. The coilspring 11 is secured at its one end to the spoke and hooked at its otherend to the rod 10. The coil spring 11 is wound about the rod 10 so thatthe end of the rod 10 is urged toward the steering shaft 3. Theresilient force of the coil spring 11 has a predetermined strength, likethat of the above-mentioned leaf spring 9.

In the embodiment as shown in FIG. 4, a support 12 and a leaf spring 13are used as the resilient means which urges the rotating shaft 6 of thesatellite gears 7 and 8 toward the steering shaft 3. The support 12 isfixed at its opposite ends to the two spokes which radially extend fromthe steering shaft 3 to the steering wheel and provided at its middleportion with a slot 14 which elongates along the radial direction of theexternal gears. The rotating shaft 6 of the satellite gears 7 and 8 isinserted in the slot 14 so that the rotating shaft can freely move alongthe radial direction of the external gears 5 in the slot 14. The leafspring 13 extends across the slot 14 and is secured at its opposite endsto the support 12. The leaf spring 13 contacts at its middle portion therotating shaft 6, whereby the rotating shaft 6 is urged toward thesteering shaft 3. Consequently, the external gears 1 and 5 are kept inengagement with the satellite gears 7 and 8 at all times. In thisembodiment, the support 12 which is firmly secured to the spoke 4 isused for supporting the rotating shaft 6. Accordingly, the stability ofthe rotating shaft is improved compared with the above-mentioned firstand second embodiments.

An operation panel 81 (see FIG. 7) is adapted to be fixed on the topsurface of the second external gear 5 as shown in FIGS. 1 to 4. Oneexample of such an operation panel is shown in FIG. 5. Referring to FIG.5, reference numeral 20 designates a horn switch which is connected withan automobile horn. The horn sounds when the horn switch is depressed.Reference numerals 21 and 22 designate a headlight switch and a parkinglamp switch. Reference numeral 23 designates a turn-off switch forheadlights and parking lamps. Reference numeral 24 designates a hazardlight switch. Reference numeral 25 designates a cover for telephoneoperation which is normally closed and adapted to be opened when thetelephone is used.

Reference numeral 26 designates a keyboard on which push buttons for thetelephone are located. Reference numeral 27 designates a display whichdisplays the telephone number etc. with ten segments. Reference numeral28 designates an indicator which is turned on when the automobile is outof the telephone call service area. The reference numeral 29 designatesan indicator which is turned on only during telephone communication.Further, reference numeral 30 designates an indicator which indicatesthat signal communication with another service area is underway and isautomatically turned on when the automobile goes out of its own servicearea. Reference numeral 31 designates a switch which is used foradjusting the brightness of the display screen. Reference numeral 32designates a muting switch which is used for interrupting the voice ofthe speaker while it is depressed. Reference numeral 33 designates atransmitting/receiving switch and is used when transmitting orreceiving. Reference numeral 34 designates a telephone communicationending switch which is depressed when the telephone communication isover. Reference numeral 35 designates a clear switch which is used toerase the display image. Reference numeral 36 is a recall switch whichreads out the telephone number as previously stored. Reference numeral37 designates a store switch which is used when storing a telephonenumber.

On the rear of the operation panel as shown in FIG. 5 is mounted acircuit board (not shown) which is connected with the above-mentionedswitches and indicators, etc. In addition, on the circuit board aremounted a signal processing section using a CPU, and a plurality ofinfrared diodes 44a, 44c and photodiodes 44b (see FIG. 6) functioning asa transmitting/receiving circuit or a signal input/output section whichwill be described hereinafter. A plurality of through holes 15 areprovided on the external gear 5 at the positions which correspond tothat of the circuit board where the infrared diodes or the photodiodesare mounted when the operation panel is secured to the external gear 5as shown in FIG. 1. These through holes 15 are spaced on a predeterminedcircle around the steering shaft. A plurality of apertures 16 areprovided on the spoke 4 along a circle having the same radius as that ofthe circle where the through holes 15 are located. A plurality ofthrough holes 17 are provided on the first external gear 1 under thespoke 4. Infrared diodes 18b and photodiodes 18a, 18c are locatedunderneath the through holes 17. In this arrangement, a plurality oflight signal transmitting paths are formed between the infrared diodes44a, 44c and photodiodes 44b mounted on the circuit board at the rear ofthe operation panel, and the infrared diodes 18b and photodiodes 18a,18c under the external gear 1. The apertures formed on the spoke 4 havea predetermined length along the circumferential direction and arespaced at a predetermined distance. These aperture lengths and distancesare selected so that at least one two-way path set out of theabove-mentioned light signal transmitting paths can be ensured even ifthe spoke 4 is moved relatively to the external gear 5 during rotationof the steering wheel. On the upper end of the steering shaft 3 isfitted a slip ring 19 which is connected with an automobile battery (notshown) through conductive lines which pass through the inside of thesteering shaft 3. A brush (not shown) which is adapted to contact theslip ring 19 is mounted on the side of the operation panel. In thismanner, a power supply to the operation panel is attained by such adrum-type slip ring 19 and the brush.

FIG. 6 is a block diagram of the signal transmitting system showing thesecond feature of the present invention. Referring to FIG. 6, the signaltransmitting system between the operation panel and the base unit of theradiotelephone is generally divided into the signal transmitting systemof the operation panel, light signal transmitting path and the signaltransmitting system of the radiotelephone base unit. CPUs are located onboth the signal transmitting system of the operation panel and thesignal transmitting system of the radiotelephone base unit. A keyboard26 and a receiving circuit 41 are connected with the input terminal ofthe CPU 40 of the operation panel, and a display 27 and a transmittingcircuit 42 are connected with the output terminal of the CPU 40. Thetransmitting circuit 42 modulates the output signal from the CPU 40 andprovides an output which is used to drive the above-mentioned infrareddiode 44a of the operation panel through a driver 43. On the other hand,an output signal emitted from the light receiving diode 44b of theoperation panel is amplified by a head amplifier 45 and supplied to thereceiving circuit 41.

One of the input terminals of the CPU 46 of the radiotelephone base unitis connected with a receiving circuit 48 through a phase locked loop(PLL) circuit 47 and the other input terminal is connected with theoutput terminal of a handset unit 49 of the radiotelephone through amultiplexer 66. One of the output terminals of the CPU 46 is connectedwith a transmitting circuit 50 and the other output terminal isconnected with the input terminal of the handset unit 49. The receivingcircuit 48 and the transmitting circuit 50, in the same manner as thecase mentioned above, are respectively connected with the photodiode 18athrough a head amplifier 51, and with the infrared diode 18b through adriver 52. Moreover, the PLL 47 which is disposed between the CPU andthe receiving circuit 48 is used to lock the frequency of the outputsignal of the receiving circuit at that of the reference signal.

The handset unit 49 is connected with a transceiver unit 53 which is inturn connected with an antenna 54. The transceiver unit 53 transmitsand/or receives signals through the antenna 54. The power supplyterminal of the handset 49 is connected with the automobile battery (notshown) through a fuse box 55. Normally, voice transmitting/receiving iscarried out by use of the handset 49.

In the signal transmitting system as shown in figures, voicetransmitting/receiving can be also carried out by use of a microphone 56(see FIG. 5) located on the operation panel, and a plane wave speakerunit 69 provided at the front of the driver in the automobile interior.Descriptions will be hereinafter made in relation to the audio signaltransmitting system using the microphone 56 and the plane wave speakerunit 69. Another microphone 56' is used in addition to the microphone 56but only the microphone 56 is exposed on the surface of the operationpanel at the upper portion of the horn switch 20. The audio signal whichis supplied through the two microphones 56 and 56' is transmitted to amicrophone amplifier 57. In the microphone amplifier 57, vibration noisewhich enters each of the two microphones is differentially amplified andeliminated. The output of the microphone amplifier 57 has its frequencycontrolled by an automatic gain control (AGC) 58 and then has its phasemodulated by a PLL 59, and the output is then supplied to the driver 60to drive the infrared diode 44c.

The light emitted from the infrared diode 44c is received by thephotodiode 18c through the above-mentioned light transmitting path. Thesignal from the photodiode 18c is amplified by a head amplifier 61 andthen demodulated by a receiving circuit 62 and a PLL 63. The demodulatedsignal is applied to a multiplexer 66 through an AGC 64 and a levelbalancer 65 and supplied to the plane wave speaker unit 69 through anAGC 67 and a power amplifier 68. The AGC 64 and the level balancer 65are used to control the howling. The level balancer 65 sets the howlinglevel and the AGC 64 controls the output level of the PLL 63 at the sethowling level range. Use of the plane wave speaker unit 69 expands thearea where no howling occurs and facilitates setting of the howlinglevel.

A head amplifier 71 and a microphone amplifier 72 are also connectedwith the multiplexer 66 through another AGC 70. A plug of a headphoneset 73 is adapted to be inserted into the input terminals of theseamplifiers. On the operation panel, a photodiode 74 is connected withthe infrared diode 44a in series (solid line) or in parallel (brokenline). The photodiode 74 is turned on in response to the light emissionof the infrared diode 44a when a signal is transmitted from theoperation panel to the radiotelephone base unit. To a display circuit 27is connected a current flow circuit 75 which controls the current flowto be supplied to the display circuit in response to the actuation of anight switch 31 on the operation panel to thereby control the blightnessof the display screen. Supply of power to the CPU is carried out by theslip ring and the brush as mentioned above. On the operation panel,switches for various items of equipment of an automobile such as hornswitch are also provided in addition to the switches of theradiotelephone. These switches are connected with the automobile'svarious equipment and battery through the means of a slip ring andbrush. The connecting means as shown in figures, like that describedabove, is an example of the disc-type slip ring but any other slip ringsuch as drum or disc types may be used.

As hereinbefore described, the signal transmitting system of the presentinvention incudes a howling control function which resolves the problemin the duplex communication using the microphone and the speaker unit,and enables easy telephone communication even during driving. Moreover,FIG. 7 is a schematic view showing the neighborhood of the driver's seatof the automobile where the operation panel stationary supportingmechanism and the signal transmitting system according to the presentinvention are incorporated. In FIG. 7, reference numerals 80, 4, and 81designate a steering wheel, a spoke, and an operation panelrespectively. As mentioned above, the microphone 56 is located on theupper portion of the surface of the operation panel and the plane wavespeaker unit is located at the front of the steering apparatus.Reference numeral 2 designates a driver's seat, on the left of which thehandset unit 49 or the radiotelephone base unit is located.

INDUSTRIAL APPLICABILITY

The operation panel stationary supporting mechanism of the presentinvention is applicable to all movable bodies such as automobiles,vessels or others having a rotary handle-type steering apparatus. Thesignal transmitting system with howling control function according tothe present invention is useful for the drivers of the movable bodies tocommunicate with others by use of the radiotelephone equipped therein.

We claim:
 1. A steering apparatus comprising a first external gear fixedon a column cover positioned under the spoke of a steering wheel, thesteering shaft of which passes through the first external gear and isfreely rotatable therein, a second external gear rotatably supported onthe upper end of the steering shaft which extends over the spoke of thesteering wheel, an operation panel fixed on the upper surface of saidsecond external gear, a rotating shaft located parallel to the steeringshaft, satellite gears secured to the upper and lower ends of saidrotating shaft and adapted to engage said first and second externalgears, a rod which is pivotably supported at its one end on the spoke ofthe steering wheel and has at its other end a bearing for rotatablysupporting the rotating shaft of the satellite gears, a coil springwhich is secured at its one end to the spoke and hooked at its other endto the rod, said coil spring being wound around the rod so that the rodis urged toward the steering shaft, whereby the rotating shaft isresiliently urged to the steering shaft.